Paper  doi  bibtex   

@article{silbert_geometry_2002,
	title = {Geometry of frictionless and frictional sphere packings},
	volume = {65},
	issn = {1063-651X, 1095-3787},
	url = {http://link.aps.org/doi/10.1103/PhysRevE.65.031304},
	doi = {10.1103/PhysRevE.65.031304},
	language = {en},
	number = {3},
	urldate = {2015-05-14TZ},
	journal = {Physical Review E},
	author = {Silbert, Leonardo E. and Ertaş, Deniz and Grest, Gary S. and Halsey, Thomas C. and Levine, Dov},
	month = feb,
	year = {2002}
}